Embodiments of the present invention relate to monitoring of a system, in particular to identify the cause of conditions outside of expected operating conditions.
There are many different types of systems that may have performance characteristics that are monitored, such as mechanical systems, including for example engines, turbines, airframes etc. A system, such as an engine, may have one or more sensors to measure various aspects of the system, for example temperature, pressure, rotational speed, fluid flow etc. The outputs from the one or more sensors may be monitored to identify characteristics of the system, for example to try to identify if the system is operating outside expected conditions. For a class or system, such as the class of commercial aero engine, there will be a recognised set of failure mechanisms for non-optimal performance characteristics indicative of non-ideal operation, such as core degradation or failure of particular mechanisms. Such failures can exhibit symptoms that have a particular failure signature of a pattern displayed by various sensed parameters.
However, a problem with monitoring such systems is that when operating in unusual environments, such as in very hot conditions, very cold conditions, high altitude etc., monitoring may indicate that there is a fault when the system is, in fact, operating satisfactorily for the particular circumstances experienced.
It would be desirable to be able to monitor a system more precisely so that false alarms are reduced and problems are identified more easily.